How to model a folded magazine?
I would model the profile of the open magazine -



then extrude it to the height of the magazine and add a solidify modifier.


One end can be scaled out to get the variation at the top. Apply the solidify and add a crease to the outer edges, then use an edge split and subsurf modifier to finish it off. Some parts can then be expanded where the pages are separated.



I would then add the "space" between the pages and the page variations to the texture.